Improved street pavement



tnittd tattt time @twine Laws Pfam N 101,100, atea Match 22, 1370.

IMPROVED STREET PAVEMENT.

The Schedule referred to in these Letters Patent and making part of thesame,

To whom it 'mail concern.-

Beit known that I, I). C. COLBY, of XVaShingtOn, in the county ofWashington and District of Columbia, have, as I believe, invented newand useful Improvements in Street Pavements, of Vood and Concrete; and Ido hereby declare the following to be a full and exact description ofthe same. reference being had to the drawings that accompany and form a'part oi' these specifications.

Figure l is a perspective view of a portion of my pavement laid.

Figure 2, wooden blocks, such as'are set to form the upper structure ofmy pavement.

Letter A, one ot the full-sized blocks, having six plane sides, and itsangles right angles. 'a

B, the space between alternate rows of the blocks, the'se arranged inlilies crosswise the street, and the spaces corresponding.

O and I), strips ot' wood lying along the base ofthe blocks A and at thebottom of the spaces B. 'lhe peculiar formation' and arrangement ofthese strips will be more fully lureinafter -f et forth, with thereasons therefor.

' E, planking, forming the substructure, which should be laid on awell-prepared bed oi"1 gravel. p

F, thick plank, ruiming erosswise beneath the abnt`- ting ends oi" theplanks It.

The objects of my invention are to secure a block'- pavement that shallbe very economical as to the iitting ot' the lumber and laying the same,and to provide with more certainty the permanent position of the blocks,although arranged in suoli a manner that any number of the said blocksmay be readily removed and replaced, when it should become necessary toreach the street below for any purpose.

My blocks have simple plane sides, but to prevent any of the iineparticles from the concrete or filling in the upper part of the spaces Bfrom falling downv and working their way beneath the blocks A, I use twostrips, C and I), each varying in thickness as to its two oppositeedges. Before using, I slightly tack the two together, as illustrated onthe right of tig. 1.

Now, having the substructure in readiness, I stand a row of blocks atthe place of beginning, across the street from curb-stone to curb-stone,then take the compound strips C and I) and place them inposition, asillustrated on the right of fig. l of the drawings, a

line oi' these extending quite across in front of the said line ofblocks, and resting upon the substructure E. i

It will be observed that "one of the strips O and D lies higher up thanits fellow, and that the two sides in Contact are beveling, sothat,\\.after a series of rows of the blocks A and the compound stripsare laid, and the iilling for the spaces B above these strips is 'to betamped in, the pressure thus brought to bear upon the top of I) willforce it down to a level with its fellow O, and the result will be tofill entirely and closely the lowerpart of the space B, and not onlyprevent all fine parts from above from falling down', but also keep theblocks more surely in place.

rIhe blocks may be six inches or more deep, three inches or so thick,and ot' such width as the lumber fronLwhich they are being formed maysuggest.

The spaces B, if to be lled with small sand and gravel, may well be notmore than one ineh wide; but j if to be filled with small stones, brokenstone, "coarse concrete, andthe like, 4they may be two inches o'r more.v

We recommend to have these spaces wide, and as much coarse material usedin filling as can be, and still form a goed, tenacious, and hardconcrete.

A broken stone, gravel, or cement substructure may well, on firm soils,be substituted for the wooden plank E.

I do not claim rising the substructure E, nor lling the spaces B withgravel, concrete, or stone, as my invention consists in making use ofthe two str ips O and D ,so formed and laid that they shall more fullyfill the lower portion of the spaces B laterally when the filling abovehas been forced down, as hereinbefore explained.

What I claim as of my invention, and desire to secure by Letters Patent,is-

The two strips O and D, when used in combination with the blocks A, andformed to operate substantially as described and set forth.

.In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

D. O. COIJBY.

XVitnesses It. H. MAnsn, J. F. Gonny.

